OCCURRENCE OF TETRACYCLINE RESISTANT BACTERIA AND RESISTANCE GENE (tetW) IN HOSPITAL AND MUNICIPAL WASTEWATERS

The occurrence and spread of antibiotic resistant bacteria (ARB) and genes in the environment is a public health concern. Wastewater is a potential source for dissemination of ARB and antibiotic resistance genes (ARGs) in the environment. The present study was conducted to determine the abundance of tetracycline resistant bacteria (TCr) and gene (tetW) in hospital and municipal wastewaters. The influence of wastewater treatment plants (WWTPs) on the fate of TCr bacteria and tet(W) gene was also investigated. A total of 66 samples from raw and final effluent of hospital and domestic WWTPs were analyzed. TCr bacteria as a major part of the heterotrophic plate count (HPC) bacteria were found in the raw wastewater and final effluent samples in a concentration ranged from 1.28 x 10(8)- 5.19 x 10(6) to 4.60x10(6)- ND (not detected) CFU/100ml, respectively. Tet(W) gene concentration in the raw wastewaters were found to be in the range of 3.87x10(7)-6.23x10(13) copies/100ml and WWTPs did not contribute in effective reduction of tet(w) gene. No significant correlation was found between the levels of let(W) gene and TCr bacteria in either raw wastewater or final effluent. The results of this study showed that TCr bacteria and tet(W) gene were present in relatively high levels in both municipal and hospital wastewaters. The results also indicated that conventional wastewater treatment plants didn't contribute in effective reduction of let(w) gene and wastewater effluents are a potential source for dissemination of let(w) gene into the natural environment.